It is well-known in the textile field to utilize fiber feeding apparatus, commonly referred to as chute feeds, for collecting fiber tuffs which are densified or compacted within the chute feed and then fed as a batt to carding machines and the like for further processing. It is also well-known that the quality of the yarn which is ultimately formed by the textile processing operation depends to a large extent on the uniformity of the density of the batt discharged from chute feed, and a number of efforts have been made to improve the uniformity of the batt density by utilizing various means for mechanically or pneumatically compressing the fiber during its movement through the chute.
For example, chute feeds have heretofore been constructed with a vertical fiber collecting chute formed by a plurality of imperforate walls which extend along the entire vertical length of the chute, with one of such imperforate walls being mounted adjacent its upper end for pivotal movement toward and away from an opposite imperforate wall. The pivoted wall is continuously oscillated to impose a mechanical compressive force on the collected fiber in the chute along virtually the entire vertical extent thereof. However, this oscillating movement of the entire chute feed wall has a tendency to permit the collected fiber between the oscillating and fixed walls to expand or open to some extent during movement of the oscillating wall away from the fixed wall, thereby partially reducing the effectiveness of the compaction of the fiber, particularly since the oscillating wall extends along virtually the entire vertical extent of the chute. Examples of chute feeds of this type are disclosed more fully in U.S. Pat. Nos. 3,896,523, and 3,728,759.
Another approach to densifying the fiber in chute feeds has been to utilize an induced air flow to transport fiber tufts to the vertical chute, and to cause the pressurized air to flow downwardly through the collected fibers in the chute to compress such fibers, typical examples of chute feeds of this type being disclosed in greater detail in U.S. Pat. Nos. 3,482,883, and 4,176,988. In some chute feeds of this type, at least one of the fixed walls forming the chute includes a fixed perforated portion adjacent the lower end of the wall through which the air is discharged or exhausted either in a continuous flow-through of the air, as disclosed for example in U.S. Pat. No. 4,136,911, or in a closed path as disclosed for example in U.S. Pat. No. 4,219,289. In either case, it will be apparent that this flow of pressurized air, after passing downwardly through the fibers collected in the chute, must pass through the perforations in lower part of chute wall at a velocity which results in some of collected fibers in the chute being held against the adjacent surface of the perforated wall. This induced holding of the fibers against the surface of the perforated wall portion adversely effects the ability of the collected fiber to move freely down through the chute, and, more importantly, it has an adverse effect on the uniformity at which such fibers will be compacted or densified at the point where maximum compression is normally obtained, namely at the lower end of the chute just prior to the fibers being discharged therefrom. These adverse effects are exacerbated when two opposed, stationary walls of the chute are perforated, as shown for example in the aforesaid U.S. Pat. No. 4,219,289, because the induced holding of the fibers against the perforated wall occurs on two sides of the collected column of fibers.